This invention is concerned with a machine for lasting side portions of shoe uppers comprising a shoe support for supporting, bottom uppermost, a shoe comprising a shoe upper on a last with an insole on the last bottom, side lasting instrumentalities comprising two wiper assemblies, arranged one at each side of the shoe support and each comprising a rotary lasting roll extending transversely of the shoe bottom and having a helical wiping element which engages the shoe upper for effecting an in-wiping force thereon as the roll rotates, together with means for effecting rotation of the rolls, and means for effecting relative movement, lengthwise of the shoe bottom, between the shoe support and the side lasting instrumentalities to cause the lasting rolls to operate progressively along opposite side portions of the shoe bottom.
One such machine is disclosed in DE-C 1817915, in the operation of which machine the lasting rolls, forming part of the side lasting instrumentalities, operate along opposite marginal portions of the shoe bottom from the region of the heel breast line toewardly, the helical wiping element of each roll serving to in-wipe the lasting margin and to press it against the insole, to which it is secured by previously applied adhesive. In other machines, e.g. the machine disclosed in US-A No. 4435869, lasting rolls are again used having helical wiping elements, but in this case they are caused to move heelwardly from a region of the forepart of the shoe bottom which has previously been lasted, the wiping elements again serving to in-wipe and press the lasting margin against the insole to secure it thereto by previously applied adhesive.
In the latter machine, the final stage of lasting the shoe is constituted by a heel seat lasting operation in which, using wiper plates, the shoe upper material constituting the lasting margin is wiped over the insole edge and secured and any excess material is distributed in the form of pleats over the marginal surface of the insole; in this way, no significant loops or folds are formed in the upper material. It will of course be appreciated that excess material frequently arises because of the shape of the upper and the need for it to conform to the shape of the last such that the lasting margin of the upper can be secured satisfactorily to the insole.
Where the operation takes place from the heel breast line region toewardly, as e.g. in the machine disclosed in DE-C No. 1817915, the excess material again arises and, where the forepart of the shoe upper has already been lasted, an unwanted fold often arises at the "boundary" between the lasted forepart portion and the progressively lasted side portion. Such a fold is very undesirable not only from a shoe-making point of view, in that it renders difficult subsequent treatment of the marginal portion of the shoe bottom, e.g. roughing and sole attaching operations, but also in that excess material in the ball region of the shoe can cause discomfort to the wearer.
Where it is desired to combine a side lasting operation using lasting rollers of the above kind with a heel seat lasting operation, it is of course desirable to operate from the heel breast line toewardly with the side lasting instrumentalities in order to "clear" the heel seat for the heel seat lasting operation, so that the overall time taken for the heel seat lasting and side lasting operations can be reduced. It will thus be appreciated that it is undesirable in such "combination" machines for the side lasting operation to take place from the boundary of the previously lasting forepart operation heelwardly, since in such circumstances it would not be economically acceptable to delay the heel seat lasting operation until the side lasting operation is completed.